\documentclass{article}

\usepackage[svgnames]{xcolor}
\usepackage{tcolorbox}
\usepackage{amsmath,amsfonts,amssymb,amsthm}
\usepackage{lipsum}
\usepackage[top=2.5cm,right=3.5cm,bottom=2.5cm,left=2.5cm]{geometry}

\tcbuselibrary{listings,skins,theorems,xparse}

\NewTotalTCBox{\maplebox}{ O{white} v}
{ colupper=black,nobeforeafter,tcbox raise base,
  arc=0pt,outer arc=0pt,colback=#1!10!white,
  colframe=#1!50!black,
  boxsep=0pt,left=1pt,right=1pt,top=2pt,bottom=2pt,
  boxrule=0pt,bottomrule=1pt,toprule=1pt}
{\lstinline[style=tcblatex,texcsstyle=*\color{blue}\bfseries]§#2§}

\begin{document}

\maplebox{\LaTeX}
\maplebox[red]{Some \LaTeX\ code}
\maplebox[blue]{$a^2+b^2=c^2$}
\maplebox[green]{\textbf{something}}

\end{document}